Code reformatting: security

[Nicholas Wilson]

Dear all,

The PCRE2 codebase has just been reformatted to have a more regular style.

This wasn't a very important change - but it does have one problem.

The entire diff is too large for anyone to read through.

I am conscious this could be a security concern for some: you may require some assurance that I didn't slip in a backdoor.

There were about 3 or 4 commits that were essentially fully-automated, and I would be happy to provide instructions on how to reproduce those, if there is any interest.

One commit _looks_ very large, but merely adjusts each line's leading indentation, so it has zero lines of change when viewed with `git diff -w` (ignore whitespace).

The second-largest commit reflows the code, and is a pure application of clang-format, so that one can also be reproduced easily. (I post-processed the diff with Python to remove the hunks that were identical-barring-whitespace across two lines; eg adding or removing a line break. Then the remainder was short enough that I was able to read and verify it myself by eye.)

The other commits I did with some regexes in a Python script - and the results were short enough that I was able to read through the changes myself carefully before committing them. So in principle, you could read them too.

I want to be transparent about this change, simply for the record.

All the best,

Nick